Michael Palin has described football superstar David Beckham as a wimp for being afraid of frogs.

Palin was interviewing Beckham about the former England captain's new documentary, Into the Unknown, which will air in Australia later this month.

In the interview posted on YouTube, Beckham reveals he was afraid of the snakes and frogs in the jungle.

"(The snake was) bigger than it looks on TV, he said.

"The frog was scary. I am not a big frog fan. I was told it was pretty dangerous. I was a little bit nervous about that."

Palin retorts: "You're a wimp really!"

Palin's comment may have been tongue in cheek but it illustrates how manicured and pampered Beckham is.

That's something the star is trying to change with the documentary, which follows Beckham and three friends for 12 days, travelling 1300 kilometres into the Amazon rainforest to spend the night with a tribe who have no idea who the mega-star is.

Beckham says he was inspired to make the documentary after realising he had never in his life been on an unscheduled trip.

His passports have been carried by other people, his flights pre-arranged and his tour agenda organised months in advance.

Before he leaves, wife Victoria fusses over his hair.

"What will you do about your hair and the humidity? It will turn you ugly," Victoria says.

After flying to Rio de Janeiro the boys continue their journey by motorbike, canoe and plane to meet the remote Yanomami tribe.

There Beckham finds delight in the fact that no-one knows who he is.

"He turns around to me and says 'what do you do as a job?' I said I was a soccer player and he said 'what's that'?

"That's obviously the first time I have had to explain what soccer is to anybody besides Victoria."

In the jungle Beckham confronts basic challenges like sleeping in a hammock and trying to figure out where to look when a naked man is standing in front of you wearing nothing but body paint.

"I've put myself into situations that I have never done before. It excited me. It unnerved me, but it is one thing that me and my friends will never forget."

It's an interesting insight into Beckhan and it's refreshing to see him strip off some of his first world problems during the course of the documentary.